White House spokesman Jay Carney would not confirm how Abu Yahya al-Libi was killed, but an American official said he was killed in a U.S. drone strike, according to the report.

Carney described al-Libi as an operational leader and a “general manager” of Al-Qaeda. He said al-Libi had a range of experience that will be hard for Al-Qaeda to replicate and brings the terror network closer to its ultimate demise than ever before.

The United States has been hunting for Al-Libi for years and placed a $1 million bounty on his head. American forces previously arrested and held him until he escaped from a U.S. prison in Afghanistan nearly seven years ago.

Al-Libi is known for his YouTube lectures and videos, one of which documented his capture by Pakistanis, his being turned over to American authorities, and his escape.

He was elevated to Al-Qaeda's No. 2 spot when Ayman al-Zawahri rose to replace former leader Osama bin Laden, who was killed last year in a raid by U.S. elite forces on his million dollar villa in Pakistan.

Pakistani intelligence officials told The Associated Press that four missiles were fired at a suspected hideout in North Waziristan, near the Afghanistan border, early Monday morning, killing al-Libi and about four others.

The suspected militants were reportedly gathered to honor a militant commander who had been killed in an early drone strike at the time of the attack, AP reported.

Sources in the region told CBS News that local intelligence agents and residents who knew of al-Libi's whereabouts say he was injured in a May 28 drone strike, and then killed in the strike Monday.